Work on artificial pancreas project nears historic end
The revolution ahead
Published 5:30 am, Monday, June 16, 2008
Researchers are edging closer to a high-tech system that would automatically regulate diabetics' blood sugar and rid them of their daily burden of pricking their fingers and injecting insulin.
The system, a so-called artificial pancreas, has been a Holy Grail of diabetes treatment for decades, a bridge to the day when a cure is finally found. It would mostly benefit Type 1 diabetics, those whose bodies have stopped making insulin, but also those Type 2 diabetics who require insulin shots.
"The artificial pancreas will revolutionize diabetes treatment," said Aaron Kowalski, a research director at the Juvenile Diabetes Research Foundation, the project's big sponsor "It will significantly lower or eliminate the risk of complications such as blindness, kidney failure, heart disease. And it will improve quality of life as people will no longer have to constantly monitor themselves."
The system already is in trials at centers in the United States and internationally. But researchers say it'll likely be another five or so years, as component parts are improved and consolidated into a single package, before the realized vision is ready to hit the market.
It wouldn't be a traditional replacement organ. Rather than physically resemble a pancreas and fit near it, it would mostly rest outside the body and strive only to duplicate function. It would build upon two existing devices — insulin pumps and continuous blood glucose monitors — that marked big steps forward in diabetes treatment in 1978 and 2005, respectively.
In the finished product, the monitor will not only measure a diabetic's blood sugar level, but signal the pump to release an appropriate amount of insulin to adjust the level into the normal range, in effect mimicking a real pancreas. A computer program, developed based on the changes in levels caused by human diet and behavior, will calculate the particular need at any given time.
The result would be the elimination of the highs and lows diabetics now experience.
Some 21 million Americans have diabetes, which is characterized by the body's inability to produce or properly use insulin, a hormone that maintains normal levels of blood sugar, or glucose, and helps convert sugar, starches and other food into energy. About 5 million diabetics take it, including as many as 3 million with Type 1.
In an effort to maintain optimal glucose control of their glucose — high levels damage blood vessels and nerves and lead to complications — conscientious diabetics will prick their fingers four to 10 times a day to test their levels. But even frequent testers don't know if their glucose skyrockets or crashes between tests — most ominously, when they're asleep.
Studies have found that even patients who measure their glucose as much as nine times a day spent less than 30 percent of the day in the normal range. Their levels were either too high or too low the rest of the time.
In that context, the Food and Drug Administration's recent approval of continuous monitors was a breakthrough. The monitor, worn like a pager and connected to a sensor placed just under the skin, tells the patient whether levels are trending up or down. If levels reach dangerously high or low levels, it sounds an alarm.
"The monitor's made things a lot easier for me," says Rob Loar, a Kingwood native and medical student diagnosed with Type 1 diabetes in 1992, when he was 6. "Because of the additional information it provides I'm able to use my pump more effectively and avoid the peaks and valleys I used to experience."
But the monitors have limitations. Their readings are usually 15 to 30 minutes behind real time. They require users to be educated and committed to the task, a requirement that's resulted in short-term studies showing mixed results. And because adoption of the device has been limited so far, insurance only sporadically covers its high cost — $1,000 plus at least $350 a month for supplies.
The fully realized artificial pancreas should change all that. Researchers predict it would be universally adopted by diabetics on insulin — and thus covered by insurance — because it'd work automatically, rendering patient involvement unnecessary.
In the first pediatric trial of a prototype of the artificial pancreas earlier this year, Yale University researchers tested it on 18 teenagers who stayed in a hospital for 36 hours and found it effectively kept glucose levels in the normal range throughout. New series of trials testing the system in less controlled settings are in the works.
But researchers acknowledge there is still much work to be done. At the moment, they say, the biggest challenge is developing a sensor that delivers accurate measurements of glucose levels to the pump in real time. Algorithms that calculate just how much insulin should be delivered at different times and in different circumstances need to be improved, though researchers say that shouldn't be an easy problem to solve.
Still, there are skeptics aplenty, some of whom complain that they have been hearing about an artificial pancreas since the 1970s, when prototypes were refrigerator-sized and hospital-based. More than 30 years later, hoping instead for a biological cure, they argue it's still just a lot of hype.
More specifically, they warn about the inevitability of mechanical failure, which could cause catastrophe if it occurred at particularly inopportune times; the burden of carrying around even more technology; and price tags double the amount of today's pumps.
Researchers respond that they are working on back-up systems in case of mechanical failure, that later-generation models of the artificial pancreas likely would be wholly under the skin and that insurers will ultimately rush to embrace it because it will dramatically reduce the $100 billion the United States now spends annually on diabetes-related medical care.
"It's important to remember that an artificial pancreas won't be a cure," said Dr. Philip Orlander, head of endocrinology at the University of Texas Medical School at Houston. "It'll still require doctor's visits and monitoring. But it would be a major improvement over current treatment, one that I'm sure all Type 1 diabetics in our clinic would be on."